Minimum secure speed of fully mechanized coal face based on critical temperature of coal spontaneous combustion

The critical temperature theory of spontaneous combustion of coal and the numerical simulation method are used to explore the minimum secure speed of fully mechanized coal face to prevent the spontaneous combustion in goaf. Combined with the actual situation of workface 31005 in a coal mine, the highest temperatures in goaf at different advancing speeds were obtained by the numerical simulation of spontaneous combustion in goaf, and then a power function equation between the highest temperature and the advancing speed was achieved by regression analysis. The advancing speed corresponding to the critical temperature value was taken as the minimum safe speed of workface based on the equation. Finally, the accuracy and reliability of the speed were verified by the actual advancing process of workface 31005. The results of this research show that the new judgment method of the minimum safety speed has a higher value to be applied in the field.